The present invention relates to telecommunications in general, and, more particularly, to a method for implementing and selecting between virtual private wireless networks.
In traditional telecommunications, most business and residential calls are carried by the telephone company over the public switched telephone network (xe2x80x9cPSTNxe2x80x9d) whose facilities are shared by the general public. One traditional characteristic of the public switched telephone network is that the fees for using the network and the telephony features available (e.g., call forwarding, caller ID, etc.) on the network are generally uniform for to all of the users of the network. A government or large business that uses millions of dollars of telecommunications service per year, however, usually chooses to have its telecommunications traffic carried by a xe2x80x9cprivate network.xe2x80x9d A private network is advantageous to the customer because it offers the customer substantial cost savings and enhanced telephony services in comparison to the public network.
Traditionally, a private telecommunications network comprised physically distinct equipment than the public network and was maintained and operated as if it were a separate, private telephone company. In contrast, technology has enabled the telephone company to offer xe2x80x9cvirtualxe2x80x9d private network service, with its lower cost and enhanced telephone features, using the same equipment as the public switched telephone network. In general, virtual private network service is advantageous for the telephone company because it allows it to manage just one physical network and to enjoy the economies of scale afforded by one large network, in contrast to maintaining one smaller public network and numerous small private networks.
As public wireless telecommunications service based on CDMA becomes available, wireless service providers are increasingly interested in offering private wireless network service to select customers. Currently, only public network service is available based on CDMA. Furthermore, if a wireless service subscriber is offered the opportunity to place a call on either the public wireless network or on a private wireless network at any given time, it would be advantageous if the wireless service subscriber could affect, on an ad hoc basis, the choice of network used to place the call.
To do this, wireless service providers have two apparent options: (1) install a separate wireless network to service each private network, or (2) change the existing air interface standards to virtual private networks and make the concomitant hardware modifications to support the changes in the air interface. Both options are considered undesirable because of the huge expense associated with implementing either option.
Some embodiments of the present invention are capable of establishing a communications channel with multiple virtual wireless networks (e.g., a public network and/or one or more private networks) on a single wireless infrastructure without many of the costs and restrictions associated with methods in the prior art. For example, embodiments of the present invention are capable of establishing a communications channel with either a public wireless network or a private wireless network on existing IS-95 CDMA facilities without changing the air interface or requiring the existence of independent private network facilities. Furthermore, some embodiments of the present invention enable a user of a wireless terminal to affect which private wireless network the wireless terminal accesses, again on existing IS-95 facilities and without changing the air interface.
These results are obtained in an illustrative embodiment of the present invention that comprises two lists of SID/NID signals: a default list and an override list. Both the default list and the override list provide a different preference for which public or private network the wireless terminal accesses when a call is placed from the wireless terminal. In other words, the default list can cause a wireless terminal to attempt access to the public network before attempting to access either private network A or private network B, and the override list can cause the wireless terminal to attempt access to private network B, then access to the public network, and then to private network A. A switch in the wireless terminal advantageously causes the wireless terminal to use either the default list of SID/NID signals or the override list of SID/NID signals. The switch can be activated either manually or by inserting the wireless terminal into a cradle in accordance with the present invention.
Other embodiments of the present invention can comprise a default list of SID/NID signals and two or more override lists of SID/NID signals and a suitable mechanism for enabling a user to select between them. Advantageously, each override list prioritizes the SID/NID signals differently so that the user can precisely affect the private network it attempts to register on.